The current-generation BMW 3-series sedan has been out for a year, and the 3-series Sports Wagon already is on sale in Europe and will hit U.S. showrooms next spring. What’s missing? The coupe, of course. After all, the 3-series started out as a two-door in 1975—a four-door wasn’t offered until 1982, when the second-generation arrived. The wait for the F30-generation 3-series coupe is coming to an end, however. At January’s Detroit auto show, BMW will unveil a 3-series–based two-door concept, previewing the next-gen 3-series coupe. However, we’re hearing from European sources that the Bavarians finally will change their nomenclature and call this car the 4-series, although BMW hasn’t confirmed that.

Not only will the 4-series coupe be previewed by the concept, but the next-gen 4-series convertible will take styling cues from the concept, as well. Unsurprisingly, the U.S. market is very important for both variants. Technical details are scarce at the moment, but don’t expect major changes from the F30 sedan’s turbocharged 2.0-liter inline-four and turbo 3.0-liter straight-six. And as far as the M4—are we the only ones struggling to come to terms with this moniker?—be prepared for a return to six cylinders, albeit boosted.

Expect further details on the 4-series concept closer to the start of the 2013 Detroit auto show, which kicks off January 14.